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From: "Eric Ruttan" <ericruttan@chartermi.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-760356@logan.com>
Subject: [FlyRotary]Belt rumnations; soliciting Opinions of racers please....
Date: Sat, 26 Feb 2005 10:33:28 -0500

As a public service announcement...
Please change the post topic to fit your post.  It just makes sense.  Get
creative!  Make a new Subject Title!

A question about belts; what are the race guys doing?  Do they see belt
failures? Is Tracy using a belt?  Ever failed?

I admit I feel more comfortable without belts, but we should be deciding
this on facts not feelings.  I don't have any facts.

I understand many automotive overhead cams use belts.  A failure will (if
interference engine) bend valves and break pistons.  These belts must be a
well known quantity.

I perceive the "danger"of a belt is the potential cascading failure.  Belt
failure takes out alt and water pump and air-conditioning (if your John
Slade).  But i guess, if this case is sufficiently rare then a secondary alt
and water pump not effected by this event will serve as a back up allowing
us to complete the flight.

To argue the other side of the coin, not using the automotive water and alt
system is throwing away cheap well engineered and proven, easy to use system
away, to get something we "feel" is better.  Remember, the most common
failure of auto conversations is the supporting systems.

Eric

From: "Marvin Kaye"
> Here's some general drive belt data from CarCareCouncil.org.  It pretty
well
> sums up the v-belt vs serpentine question:
>
> """
> Description: Fan belt is the traditional term for what today is called a
drive
> belt. Drive belts are made of reinforced, high-tensile strength cords and
> synthetic rubber. They connect the engine to front-mounted accessories.
Belts
> come in two different types: The traditional V-belt (cross-section of
belts
> has a V-shape for V-shaped pulleys) and the serpentine belt (also called
> Poly-V, Poly-Rib, Multi-Rib, and Micro-V belt), which uses multiple Vs for
> more positive contact with its mating pulleys.
>
> Purpose: Drive belts provide power to engine-mounted accessories like the
> power steering pump, air conditioning compressor, mechanical cooling fan,
and
> air injection pump. Serpentine belts are now used on almost all vehicles.
>
> Maintenance Tips/Suggestions: Studies show that the chances of a drive
belt
> failure rises dramatically after four years or 36,000 miles for V-belts,
> 50,000 miles for serpentine belts. This doesn?t mean that the belts
shouldn?t
> be inspected before then, though. The belts should be checked every time
the
> oil is changed to make sure they?re OK and properly tightened. When
checking
> V-belts, a slipping belt usually has shiny sidewalls (glazing) caused by
heat
> from sliding in the pulleys. The glazing often causes a chattering,
slapping
> or squealing noise. And, because the glazing hardens the belt, it's prone
to
> cracking and early failure. Belt slippage often occurs because of low
tension,
> the wrong belt, or grease or oil. Missing chunks, or separating layers of
the
> belt often hint at a dousing of oil or grease. The source of the oil or
grease
> needs to be corrected before installing a new belt. A V-belt with any of
these
> conditions should be replaced as soon as possible. On serpentine belts,
> inspect the belt closely for any cracks in the ribbed area. Also check the
> backside of the belt for grooves, fraying, or splitting. Although random
> cracks across the ribs are a sign of normal belt wear and don?t mean the
belt
> will fail immediately, it?s a good idea to replace the belt the next time
your
> car is serviced.
> """